Last frost date in Mequon, WI

Average last frost

May 6

Expect the last frost in Mequon around May 6. Frost after May 25 happens in only one year out of ten. The first fall frost usually arrives about October 8, which leaves 154 frost-free days. An early freeze before September 26 happens one year in ten.

Safe after (10% risk): May 25
Average first frost: Oct 8
Frost-free season: 154 days
Hard freeze (28°F) ends: Apr 24

Next 7 nights in Mequon

No frost in the next 7 nights

Later than usual: the average first frost here is October 8.

National Weather Service forecast, updated Oct 22, 12:57 UTC

ThuOct 2248°
FriOct 2349°
SatOct 2452°
SunOct 2550°
MonOct 2645°
TueOct 2743°
WedOct 2844°

Frost risk through the year at Germantown, 5.7 miles from Mequon.

Planting calendar for Mequon

Windows count forward or back from the average frost dates above. Click a crop for dates across Wisconsin.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost

Warm-season crops

JanFebMarAprMayJunJulAugSepOctNovDec

TomatoesMay 13–May 27

PumpkinsMay 20–Jun 3

SunflowersMay 6–May 27

CucumbersMay 20–May 27

CornMay 13–May 27

Sweet potatoesMay 27–Jun 10

WatermelonMay 20–Jun 3

Green beansMay 13–Jun 3

ZucchiniMay 13–May 27

OkraMay 27–Jun 10

PeppersMay 20–Jun 3

BasilMay 13–May 27

Butternut squashMay 13–May 27

CantaloupeMay 20–Jun 3

EggplantMay 20–Jun 3

Cool-season crops

JanFebMarAprMayJunJulAugSepOctNovDec

PotatoesApr 8–Apr 22

OnionsMar 25–Apr 15

CarrotsApr 15–May 20

LettuceApr 22–May 13

BroccoliApr 8–Apr 22

BeetsApr 8–May 20

PeasMar 25–Apr 8

CabbageApr 8–Apr 22

RadishesApr 1–May 13

Brussels sproutsApr 22–May 6

SpinachMar 25–Apr 15

CilantroApr 22–May 13

KaleApr 8–Apr 22

Collard greensApr 8–Apr 22

TurnipsApr 8–Apr 22

DillMay 6–May 20

CeleryMay 13–May 20

CauliflowerApr 22–May 6

LeeksApr 22–May 6

Swiss chardApr 22–May 20

ParsleyApr 22–May 13

Fall bulbs and garlic

JanFebMarAprMayJunJulAugSepOctNovDec

Tulip bulbsSep 24–Oct 29

GarlicSep 17–Oct 22

Daffodil bulbsSep 10–Oct 22

Perennials

JanFebMarAprMayJunJulAugSepOctNovDec

StrawberriesApr 8–Apr 22

AsparagusApr 8–Apr 22

Frost probabilities

Threshold	Spring, 90% chance later	Spring, 50%	Spring, 10%	Fall, 10% chance earlier	Fall, 50%	Fall, 90%
Light frost, 32°F	Apr 22	May 6	May 25	Sep 26	Oct 8	Oct 24
Hard freeze, 28°F	Apr 9	Apr 24	May 12	Oct 4	Oct 20	Nov 3

Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.

Where these numbers come from

NOAA station Germantown (USC00473058) sits 5.7 miles from the center of Mequon at 850 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.

Questions

When is the last frost in Mequon, WI?

The average last frost date in Mequon is May 6, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 25.

When is the first frost in Mequon?

The first frost in fall usually comes around October 8. One year in ten it arrives before September 26.

How long is the growing season in Mequon?

About 154 days between the average last and first frost.

When should I plant tomatoes in Mequon?

Plant tomato seedlings outside from May 13 to May 27. Start seeds indoors six to eight weeks earlier.

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